HDFS-10320. Rack failures may result in NN terminate. (Xiao Chen via mingma)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/NetworkTopology.java

@@ -29,13 +29,13 @@ import java.util.concurrent.locks.ReadWriteLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 
 import com.google.common.annotations.VisibleForTesting;
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.CommonConfigurationKeysPublic;
 import org.apache.hadoop.util.ReflectionUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import com.google.common.base.Preconditions;
 import com.google.common.collect.Lists;
@@ -54,8 +54,8 @@ import com.google.common.collect.Lists;
 public class NetworkTopology {
   public final static String DEFAULT_RACK = "/default-rack";
   public final static int DEFAULT_HOST_LEVEL = 2;
-  public static final Log LOG =
+  public static final Logger LOG =
-    LogFactory.getLog(NetworkTopology.class);
+      LoggerFactory.getLogger(NetworkTopology.class);
 
   public static class InvalidTopologyException extends RuntimeException {
     private static final long serialVersionUID = 1L;
@@ -442,9 +442,7 @@ public class NetworkTopology {
           }
         }
       }
-      if(LOG.isDebugEnabled()) {
+      LOG.debug("NetworkTopology became:\n{}", this.toString());
-        LOG.debug("NetworkTopology became:\n" + this.toString());
-      }
     } finally {
       netlock.writeLock().unlock();
     }
@@ -517,9 +515,7 @@ public class NetworkTopology {
           numOfRacks--;
         }
       }
-      if(LOG.isDebugEnabled()) {
+      LOG.debug("NetworkTopology became:\n{}", this.toString());
-        LOG.debug("NetworkTopology became:\n" + this.toString());
-      }
     } finally {
       netlock.writeLock().unlock();
     }
@@ -717,26 +713,45 @@ public class NetworkTopology {
     r.setSeed(seed);
   }
 
-  /** randomly choose one node from <i>scope</i>
+  /**
-   * if scope starts with ~, choose one from the all nodes except for the
+   * Randomly choose a node.
-   * ones in <i>scope</i>; otherwise, choose one from <i>scope</i>
+   *
    * @param scope range of nodes from which a node will be chosen
    * @return the chosen node
+   *
+   * @see #chooseRandom(String, Collection)
    */
-  public Node chooseRandom(String scope) {
+  public Node chooseRandom(final String scope) {
+    return chooseRandom(scope, null);
+  }
+
+  /**
+   * Randomly choose one node from <i>scope</i>.
+   *
+   * If scope starts with ~, choose one from the all nodes except for the
+   * ones in <i>scope</i>; otherwise, choose one from <i>scope</i>.
+   * If excludedNodes is given, choose a node that's not in excludedNodes.
+   *
+   * @param scope range of nodes from which a node will be chosen
+   * @param excludedNodes nodes to be excluded from
+   * @return the chosen node
+   */
+  public Node chooseRandom(final String scope,
+      final Collection<Node> excludedNodes) {
     netlock.readLock().lock();
     try {
       if (scope.startsWith("~")) {
-        return chooseRandom(NodeBase.ROOT, scope.substring(1));
+        return chooseRandom(NodeBase.ROOT, scope.substring(1), excludedNodes);
       } else {
-        return chooseRandom(scope, null);
+        return chooseRandom(scope, null, excludedNodes);
       }
     } finally {
       netlock.readLock().unlock();
     }
   }
 
-  private Node chooseRandom(String scope, String excludedScope){
+  private Node chooseRandom(final String scope, String excludedScope,
+      final Collection<Node> excludedNodes) {
     if (excludedScope != null) {
       if (scope.startsWith(excludedScope)) {
         return null;
@@ -747,7 +762,8 @@ public class NetworkTopology {
     }
     Node node = getNode(scope);
     if (!(node instanceof InnerNode)) {
-      return node;
+      return excludedNodes != null && excludedNodes.contains(node) ?
+          null : node;
     }
     InnerNode innerNode = (InnerNode)node;
     int numOfDatanodes = innerNode.getNumOfLeaves();
@@ -762,12 +778,36 @@ public class NetworkTopology {
       }
     }
     if (numOfDatanodes == 0) {
-      throw new InvalidTopologyException(
+      LOG.warn("Failed to find datanode (scope=\"{}\" excludedScope=\"{}\").",
-          "Failed to find datanode (scope=\"" + String.valueOf(scope) +
+          String.valueOf(scope), String.valueOf(excludedScope));
-          "\" excludedScope=\"" + String.valueOf(excludedScope) + "\").");
+      return null;
     }
+    Node ret = null;
+    final int availableNodes;
+    if (excludedScope == null) {
+      availableNodes = countNumOfAvailableNodes(scope, excludedNodes);
+    } else {
+      availableNodes =
+          countNumOfAvailableNodes("~" + excludedScope, excludedNodes);
+    }
+    LOG.debug("Choosing random from {} available nodes on node {},"
+        + " scope={}, excludedScope={}, excludeNodes={}", availableNodes,
+        innerNode.toString(), scope, excludedScope, excludedNodes);
+    if (availableNodes > 0) {
+      do {
         int leaveIndex = r.nextInt(numOfDatanodes);
-    return innerNode.getLeaf(leaveIndex, node);
+        ret = innerNode.getLeaf(leaveIndex, node);
+        if (excludedNodes == null || !excludedNodes.contains(ret)) {
+          break;
+        } else {
+          LOG.debug("Node {} is excluded, continuing.", ret);
+        }
+        // We've counted numOfAvailableNodes inside the lock, so there must be
+        // at least 1 satisfying node. Keep trying until we found it.
+      } while (true);
+    }
+    LOG.debug("chooseRandom returning {}", ret);
+    return ret;
   }
 
   /** return leaves in <i>scope</i>
@@ -795,6 +835,7 @@ public class NetworkTopology {
    * @param excludedNodes a list of nodes
    * @return number of available nodes
    */
+  @VisibleForTesting
   public int countNumOfAvailableNodes(String scope,
                                       Collection<Node> excludedNodes) {
     boolean isExcluded=false;
@@ -807,6 +848,7 @@ public class NetworkTopology {
     int excludedCountOffScope = 0; // the number of nodes outside scope & excludedNodes
     netlock.readLock().lock();
     try {
+      if (excludedNodes != null) {
         for (Node node : excludedNodes) {
           node = getNode(NodeBase.getPath(node));
           if (node == null) {
@@ -819,6 +861,7 @@ public class NetworkTopology {
             excludedCountOffScope++;
           }
         }
+      }
       Node n = getNode(scope);
       int scopeNodeCount = 0;
       if (n != null) {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/AvailableSpaceBlockPlacementPolicy.java

@@ -21,6 +21,7 @@ package org.apache.hadoop.hdfs.server.blockmanagement;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_AVAILABLE_SPACE_BLOCK_PLACEMENT_POLICY_BALANCED_SPACE_PREFERENCE_FRACTION_KEY;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_AVAILABLE_SPACE_BLOCK_PLACEMENT_POLICY_BALANCED_SPACE_PREFERENCE_FRACTION_DEFAULT;
 
+import java.util.Collection;
 import java.util.Random;
 
 import org.apache.commons.logging.Log;
@@ -28,6 +29,7 @@ import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.net.NetworkTopology;
+import org.apache.hadoop.net.Node;
 
 /**
  * Space balanced block placement policy.
@@ -68,9 +70,12 @@ public class AvailableSpaceBlockPlacementPolicy extends
   }
 
   @Override
-  protected DatanodeDescriptor chooseDataNode(String scope) {
+  protected DatanodeDescriptor chooseDataNode(final String scope,
-    DatanodeDescriptor a = (DatanodeDescriptor) clusterMap.chooseRandom(scope);
+      final Collection<Node> excludedNode) {
-    DatanodeDescriptor b = (DatanodeDescriptor) clusterMap.chooseRandom(scope);
+    DatanodeDescriptor a =
+        (DatanodeDescriptor) clusterMap.chooseRandom(scope, excludedNode);
+    DatanodeDescriptor b =
+        (DatanodeDescriptor) clusterMap.chooseRandom(scope, excludedNode);
     int ret = compareDataNode(a, b);
     if (ret == 0) {
       return a;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicyDefault.java

@@ -21,6 +21,7 @@ import static org.apache.hadoop.util.Time.monotonicNow;
 
 import java.util.*;
 
+import com.google.common.base.Preconditions;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hdfs.AddBlockFlag;
@@ -643,10 +644,9 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
   /** 
    * Choose <i>numOfReplicas</i> nodes from the racks 
    * that <i>localMachine</i> is NOT on.
-   * if not enough nodes are available, choose the remaining ones 
+   * If not enough nodes are available, choose the remaining ones
    * from the local rack
    */
-    
   protected void chooseRemoteRack(int numOfReplicas,
                                 DatanodeDescriptor localMachine,
                                 Set<Node> excludedNodes,
@@ -702,10 +702,6 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
                             boolean avoidStaleNodes,
                             EnumMap<StorageType, Integer> storageTypes)
                             throws NotEnoughReplicasException {
-
-    int numOfAvailableNodes = clusterMap.countNumOfAvailableNodes(
-        scope, excludedNodes);
-    int refreshCounter = numOfAvailableNodes;
     StringBuilder builder = null;
     if (LOG.isDebugEnabled()) {
       builder = debugLoggingBuilder.get();
@@ -714,18 +710,22 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
     }
     boolean badTarget = false;
     DatanodeStorageInfo firstChosen = null;
-    while(numOfReplicas > 0 && numOfAvailableNodes > 0) {
+    while (numOfReplicas > 0) {
-      DatanodeDescriptor chosenNode = chooseDataNode(scope);
+      DatanodeDescriptor chosenNode = chooseDataNode(scope, excludedNodes);
-      if (excludedNodes.add(chosenNode)) { //was not in the excluded list
+      if (chosenNode == null) {
-        if (LOG.isDebugEnabled()) {
+        break;
-          builder.append("\nNode ").append(NodeBase.getPath(chosenNode)).append(" [");
+      }
+      Preconditions.checkState(excludedNodes.add(chosenNode), "chosenNode "
+          + chosenNode + " is already in excludedNodes " + excludedNodes);
+      if (LOG.isDebugEnabled()) {
+        builder.append("\nNode ").append(NodeBase.getPath(chosenNode))
+            .append(" [");
       }
-        numOfAvailableNodes--;
       DatanodeStorageInfo storage = null;
       if (isGoodDatanode(chosenNode, maxNodesPerRack, considerLoad,
           results, avoidStaleNodes)) {
         for (Iterator<Map.Entry<StorageType, Integer>> iter = storageTypes
-              .entrySet().iterator(); iter.hasNext(); ) {
+            .entrySet().iterator(); iter.hasNext();) {
           Map.Entry<StorageType, Integer> entry = iter.next();
           storage = chooseStorage4Block(
               chosenNode, blocksize, results, entry.getKey());
@@ -734,8 +734,7 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
             if (firstChosen == null) {
               firstChosen = storage;
             }
-              // add node and related nodes to excludedNode
+            // add node (subclasses may also add related nodes) to excludedNode
-              numOfAvailableNodes -=
             addToExcludedNodes(chosenNode, excludedNodes);
             int num = entry.getValue();
             if (num == 1) {
@@ -746,7 +745,6 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
             break;
           }
         }
-        }
 
         if (LOG.isDebugEnabled()) {
           builder.append("\n]");
@@ -755,16 +753,7 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
         // If no candidate storage was found on this DN then set badTarget.
         badTarget = (storage == null);
       }
-      // Refresh the node count. If the live node count became smaller,
-      // but it is not reflected in this loop, it may loop forever in case
-      // the replicas/rack cannot be satisfied.
-      if (--refreshCounter == 0) {
-        numOfAvailableNodes = clusterMap.countNumOfAvailableNodes(scope,
-            excludedNodes);
-        refreshCounter = numOfAvailableNodes;
     }
-    }
-      
     if (numOfReplicas>0) {
       String detail = enableDebugLogging;
       if (LOG.isDebugEnabled()) {
@@ -785,8 +774,9 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
    * Choose a datanode from the given <i>scope</i>.
    * @return the chosen node, if there is any.
    */
-  protected DatanodeDescriptor chooseDataNode(final String scope) {
+  protected DatanodeDescriptor chooseDataNode(final String scope,
-    return (DatanodeDescriptor) clusterMap.chooseRandom(scope);
+      final Collection<Node> excludedNodes) {
+    return (DatanodeDescriptor) clusterMap.chooseRandom(scope, excludedNodes);
   }
 
   /**

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/web/resources/NamenodeWebHdfsMethods.java

@@ -81,7 +81,6 @@ import org.apache.hadoop.hdfs.web.resources.*;
 import org.apache.hadoop.io.Text;
 import org.apache.hadoop.ipc.RetriableException;
 import org.apache.hadoop.ipc.Server;
-import org.apache.hadoop.net.NetworkTopology.InvalidTopologyException;
 import org.apache.hadoop.net.Node;
 import org.apache.hadoop.net.NodeBase;
 import org.apache.hadoop.security.Credentials;
@@ -225,7 +224,7 @@ public class NamenodeWebHdfsMethods {
     } 
 
     return (DatanodeDescriptor)bm.getDatanodeManager().getNetworkTopology(
-        ).chooseRandom(NodeBase.ROOT);
+        ).chooseRandom(NodeBase.ROOT, excludes);
   }
 
   /**
@@ -265,11 +264,11 @@ public class NamenodeWebHdfsMethods {
       final long blocksize, final String excludeDatanodes,
       final Param<?, ?>... parameters) throws URISyntaxException, IOException {
     final DatanodeInfo dn;
-    try {
     dn = chooseDatanode(namenode, path, op, openOffset, blocksize,
         excludeDatanodes);
-    } catch (InvalidTopologyException ite) {
+    if (dn == null) {
-      throw new IOException("Failed to find datanode, suggest to check cluster health.", ite);
+      throw new IOException("Failed to find datanode, suggest to check cluster"
+          + " health. excludeDatanodes=" + excludeDatanodes);
     }
 
     final String delegationQuery;

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/net/TestNetworkTopology.java

@@ -23,8 +23,11 @@ import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
+import java.util.Collection;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Map;
+import java.util.Set;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -38,13 +41,18 @@ import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor;
 import org.apache.hadoop.hdfs.server.protocol.NamenodeProtocols;
 import org.junit.Assert;
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.Timeout;
 
 public class TestNetworkTopology {
   private static final Log LOG = LogFactory.getLog(TestNetworkTopology.class);
   private final static NetworkTopology cluster = new NetworkTopology();
   private DatanodeDescriptor dataNodes[];
 
+  @Rule
+  public Timeout testTimeout = new Timeout(30000);
+
   @Before
   public void setupDatanodes() {
     dataNodes = new DatanodeDescriptor[] {
@@ -272,16 +280,18 @@ public class TestNetworkTopology {
    * @return the frequency that nodes were chosen
    */
   private Map<Node, Integer> pickNodesAtRandom(int numNodes,
-      String excludedScope) {
+      String excludedScope, Collection<Node> excludedNodes) {
     Map<Node, Integer> frequency = new HashMap<Node, Integer>();
     for (DatanodeDescriptor dnd : dataNodes) {
       frequency.put(dnd, 0);
     }
 
     for (int j = 0; j < numNodes; j++) {
-      Node random = cluster.chooseRandom(excludedScope);
+      Node random = cluster.chooseRandom(excludedScope, excludedNodes);
+      if (random != null) {
         frequency.put(random, frequency.get(random) + 1);
       }
+    }
     return frequency;
   }
 
@@ -291,7 +301,7 @@ public class TestNetworkTopology {
   @Test
   public void testChooseRandomExcludedNode() {
     String scope = "~" + NodeBase.getPath(dataNodes[0]);
-    Map<Node, Integer> frequency = pickNodesAtRandom(100, scope);
+    Map<Node, Integer> frequency = pickNodesAtRandom(100, scope, null);
 
     for (Node key : dataNodes) {
       // all nodes except the first should be more than zero
@@ -304,7 +314,7 @@ public class TestNetworkTopology {
    */
   @Test
   public void testChooseRandomExcludedRack() {
-    Map<Node, Integer> frequency = pickNodesAtRandom(100, "~" + "/d2");
+    Map<Node, Integer> frequency = pickNodesAtRandom(100, "~" + "/d2", null);
     // all the nodes on the second rack should be zero
     for (int j = 0; j < dataNodes.length; j++) {
       int freq = frequency.get(dataNodes[j]);
@@ -316,6 +326,59 @@ public class TestNetworkTopology {
     }
   }
 
+  /**
+   * This test checks that chooseRandom works for a list of excluded nodes.
+   */
+  @Test
+  public void testChooseRandomExcludedNodeList() {
+    String scope = "~" + NodeBase.getPath(dataNodes[0]);
+    Set<Node> excludedNodes = new HashSet<>();
+    excludedNodes.add(dataNodes[3]);
+    excludedNodes.add(dataNodes[5]);
+    excludedNodes.add(dataNodes[7]);
+    excludedNodes.add(dataNodes[9]);
+    excludedNodes.add(dataNodes[13]);
+    excludedNodes.add(dataNodes[18]);
+    Map<Node, Integer> frequency = pickNodesAtRandom(100, scope, excludedNodes);
+
+    assertEquals("dn[3] should be excluded", 0,
+        frequency.get(dataNodes[3]).intValue());
+    assertEquals("dn[5] should be exclude18d", 0,
+        frequency.get(dataNodes[5]).intValue());
+    assertEquals("dn[7] should be excluded", 0,
+        frequency.get(dataNodes[7]).intValue());
+    assertEquals("dn[9] should be excluded", 0,
+        frequency.get(dataNodes[9]).intValue());
+    assertEquals("dn[13] should be excluded", 0,
+        frequency.get(dataNodes[13]).intValue());
+    assertEquals("dn[18] should be excluded", 0,
+        frequency.get(dataNodes[18]).intValue());
+    for (Node key : dataNodes) {
+      if (excludedNodes.contains(key)) {
+        continue;
+      }
+      // all nodes except the first should be more than zero
+      assertTrue(frequency.get(key) > 0 || key == dataNodes[0]);
+    }
+  }
+
+  /**
+   * This test checks that chooseRandom works when all nodes are excluded.
+   */
+  @Test
+  public void testChooseRandomExcludeAllNodes() {
+    String scope = "~" + NodeBase.getPath(dataNodes[0]);
+    Set<Node> excludedNodes = new HashSet<>();
+    for (int i = 0; i < dataNodes.length; i++) {
+      excludedNodes.add(dataNodes[i]);
+    }
+    Map<Node, Integer> frequency = pickNodesAtRandom(100, scope, excludedNodes);
+    for (Node key : dataNodes) {
+      // all nodes except the first should be more than zero
+      assertTrue(frequency.get(key) == 0);
+    }
+  }
+
   @Test(timeout=180000)
   public void testInvalidNetworkTopologiesNotCachedInHdfs() throws Exception {
     // start a cluster